How to resolve BackgroundContainer.dll error on startup?

When I start my desktop it gives me an error about BackgroundContainer.dll.

How to get rid of it?

I found nothing when i started regedit.exe and searched (F3 or CTRL+F) for BackgroundContainer.dll

This was a malware. It was removed by your AntiVirus Scanner, but the registry entries are still present to start the malware at startup.

Start regedit.exe and search (F3 or CTRL+F) for BackgroundContainer.dll and delete all entries you find.

To be safe, make a full scan with an AntiVirus Scanner like Microsoft Security Essentials/ Defender and also scan your PC with Malwarebytes' Anti-Malware.

If you can find nothing in the registry, download and run Autoruns from sysinterals and look here for an entry " BackgroundContainer". Look under logon and scheduled task first. When found, left click on the entry to highlight it. Then right click on your mouse and select delete from the menu that comes up for that entry. Right click on delete to delete that entry. Be careful to only delete the entry/entries you want to permanently delete.